package com.student.dao.impl;

import com.student.bean.PageBean;
import com.student.bean.User;
import com.student.bean.UserQuery;
import com.student.dao.UserDao;
import com.student.util.DBUtil;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.sql.Types;
import java.util.ArrayList;
import java.util.List;

public class UserDaoImpl implements UserDao {

    private static final String BASE_COLUMNS =
            "u.id, u.username, u.password, u.salt, u.student_no, u.real_name, u.gender, u.age, "
                    + "u.email, u.phone, u.address, u.avatar, u.clazz_id, u.role, u.status, "
                    + "u.fail_count, u.lock_until, u.create_time";

    private static final String JOIN_CLAZZ =
            " FROM users u LEFT JOIN clazz c ON u.clazz_id = c.id "
                    + "LEFT JOIN major m ON c.major_id = m.id "
                    + "LEFT JOIN department d ON m.department_id = d.id ";

    @Override
    public User findByUsernameAndPassword(String username, String password) {
        String sql = "SELECT " + BASE_COLUMNS + JOIN_CLAZZ + " WHERE u.username = ? AND u.password = ?";
        return queryOne(sql, ps -> {
            ps.setString(1, username);
            ps.setString(2, password);
        });
    }

    @Override
    public User findByUsername(String username) {
        String sql = "SELECT " + BASE_COLUMNS + ", c.name AS clazz_name, m.name AS major_name, d.name AS dept_name "
                + JOIN_CLAZZ + " WHERE u.username = ?";
        return queryOne(sql, ps -> ps.setString(1, username));
    }

    @Override
    public User findById(int id) {
        String sql = "SELECT " + BASE_COLUMNS + ", c.name AS clazz_name, m.name AS major_name, d.name AS dept_name "
                + JOIN_CLAZZ + " WHERE u.id = ?";
        return queryOne(sql, ps -> ps.setInt(1, id));
    }

    @Override
    public User findByStudentNo(String studentNo) {
        String sql = "SELECT " + BASE_COLUMNS + ", c.name AS clazz_name, m.name AS major_name, d.name AS dept_name "
                + JOIN_CLAZZ + " WHERE u.student_no = ?";
        return queryOne(sql, ps -> ps.setString(1, studentNo));
    }

    @Override
    public boolean insert(User user) {
        String sql = "INSERT INTO users (username, password, salt, student_no, real_name, gender, age, "
                + "email, phone, address, avatar, clazz_id, role, status) "
                + "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql);
            fillInsertParams(ps, user);
            return ps.executeUpdate() > 0;
        } catch (SQLException e) {
            throw new RuntimeException("新增用户失败", e);
        } finally {
            DBUtil.close(conn, ps);
        }
    }

    @Override
    public boolean update(User user) {
        String sql = "UPDATE users SET username=?, student_no=?, real_name=?, gender=?, age=?, email=?, "
                + "phone=?, address=?, avatar=?, clazz_id=?, role=?, status=? WHERE id=?";
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql);
            ps.setString(1, user.getUsername());
            setStringOrNull(ps, 2, user.getStudentNo());
            ps.setString(3, user.getRealName());
            ps.setString(4, user.getGender());
            setIntOrNull(ps, 5, user.getAge());
            ps.setString(6, user.getEmail());
            ps.setString(7, user.getPhone());
            ps.setString(8, user.getAddress());
            setStringOrNull(ps, 9, user.getAvatar());
            setIntOrNull(ps, 10, user.getClazzId());
            ps.setInt(11, user.getRole() != null ? user.getRole() : User.ROLE_STUDENT);
            ps.setInt(12, user.getStatus() != null ? user.getStatus() : User.STATUS_ACTIVE);
            ps.setInt(13, user.getId());
            return ps.executeUpdate() > 0;
        } catch (SQLException e) {
            throw new RuntimeException("更新用户失败", e);
        } finally {
            DBUtil.close(conn, ps);
        }
    }

    @Override
    public boolean updateProfile(User user) {
        String sql = "UPDATE users SET real_name=?, gender=?, age=?, email=?, phone=?, address=? WHERE id=?";
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql);
            ps.setString(1, user.getRealName());
            ps.setString(2, user.getGender());
            setIntOrNull(ps, 3, user.getAge());
            ps.setString(4, user.getEmail());
            ps.setString(5, user.getPhone());
            ps.setString(6, user.getAddress());
            ps.setInt(7, user.getId());
            return ps.executeUpdate() > 0;
        } catch (SQLException e) {
            throw new RuntimeException("更新用户资料失败", e);
        } finally {
            DBUtil.close(conn, ps);
        }
    }

    @Override
    public boolean updateAvatar(int userId, String avatar) {
        String sql = "UPDATE users SET avatar=? WHERE id=?";
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql);
            ps.setString(1, avatar);
            ps.setInt(2, userId);
            return ps.executeUpdate() > 0;
        } catch (SQLException e) {
            throw new RuntimeException("更新头像失败", e);
        } finally {
            DBUtil.close(conn, ps);
        }
    }

    @Override
    public boolean delete(int id) {
        String sql = "DELETE FROM users WHERE id = ? AND role = 0";
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql);
            ps.setInt(1, id);
            return ps.executeUpdate() > 0;
        } catch (SQLException e) {
            throw new RuntimeException("删除用户失败", e);
        } finally {
            DBUtil.close(conn, ps);
        }
    }

    @Override
    public int count(UserQuery query) {
        StringBuilder sql = new StringBuilder("SELECT COUNT(*) FROM users u WHERE 1=1");
        List<Object> params = appendQueryConditions(sql, query);
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql.toString());
            setParams(ps, params);
            rs = ps.executeQuery();
            if (rs.next()) {
                return rs.getInt(1);
            }
        } catch (SQLException e) {
            throw new RuntimeException("统计用户数量失败", e);
        } finally {
            DBUtil.close(conn, ps, rs);
        }
        return 0;
    }

    @Override
    public List<User> findList(UserQuery query, int startIndex, int pageSize) {
        StringBuilder sql = new StringBuilder("SELECT " + BASE_COLUMNS
                + ", c.name AS clazz_name, m.name AS major_name, d.name AS dept_name " + JOIN_CLAZZ + " WHERE 1=1");
        List<Object> params = appendQueryConditions(sql, query);
        sql.append(" ORDER BY u.id DESC LIMIT ?, ?");
        params.add(startIndex);
        params.add(pageSize);

        List<User> list = new ArrayList<>();
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql.toString());
            setParams(ps, params);
            rs = ps.executeQuery();
            while (rs.next()) {
                list.add(mapRow(rs));
            }
        } catch (SQLException e) {
            throw new RuntimeException("分页查询用户失败", e);
        } finally {
            DBUtil.close(conn, ps, rs);
        }
        return list;
    }

    @Override
    public PageBean<User> findPage(UserQuery query) {
        PageBean<User> page = new PageBean<>(query.getCurrentPage(), query.getPageSize());
        page.setTotalCount(count(query));
        page.setData(findList(query, page.getStartIndex(), page.getPageSize()));
        return page;
    }

    @Override
    public PageBean<User> findPendingRegister(int currentPage, int pageSize) {
        UserQuery query = new UserQuery();
        query.setStatus(User.STATUS_PENDING);
        query.setRole(User.ROLE_STUDENT);
        query.setCurrentPage(currentPage);
        query.setPageSize(pageSize);
        return findPage(query);
    }

    @Override
    public boolean updatePassword(int userId, String password, String salt) {
        String sql = "UPDATE users SET password=?, salt=?, fail_count=0, lock_until=NULL WHERE id=?";
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql);
            ps.setString(1, password);
            ps.setString(2, salt);
            ps.setInt(3, userId);
            return ps.executeUpdate() > 0;
        } catch (SQLException e) {
            throw new RuntimeException("更新密码失败", e);
        } finally {
            DBUtil.close(conn, ps);
        }
    }

    @Override
    public boolean updateFailCount(int userId, int failCount) {
        String sql = "UPDATE users SET fail_count=? WHERE id=?";
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql);
            ps.setInt(1, failCount);
            ps.setInt(2, userId);
            return ps.executeUpdate() > 0;
        } catch (SQLException e) {
            throw new RuntimeException("更新失败次数失败", e);
        } finally {
            DBUtil.close(conn, ps);
        }
    }

    @Override
    public boolean lockUser(int userId, java.util.Date lockUntil) {
        String sql = "UPDATE users SET lock_until=? WHERE id=?";
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql);
            if (lockUntil != null) {
                ps.setTimestamp(1, new Timestamp(lockUntil.getTime()));
            } else {
                ps.setNull(1, Types.TIMESTAMP);
            }
            ps.setInt(2, userId);
            return ps.executeUpdate() > 0;
        } catch (SQLException e) {
            throw new RuntimeException("锁定用户失败", e);
        } finally {
            DBUtil.close(conn, ps);
        }
    }

    @Override
    public boolean updateStatus(int userId, int status) {
        String sql = "UPDATE users SET status=? WHERE id=?";
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql);
            ps.setInt(1, status);
            ps.setInt(2, userId);
            return ps.executeUpdate() > 0;
        } catch (SQLException e) {
            throw new RuntimeException("更新用户状态失败", e);
        } finally {
            DBUtil.close(conn, ps);
        }
    }

    @Override
    public List<User> findAllStudents() {
        UserQuery query = new UserQuery();
        query.setRole(User.ROLE_STUDENT);
        query.setCurrentPage(1);
        query.setPageSize(Integer.MAX_VALUE);
        return findList(query, 0, Integer.MAX_VALUE);
    }

    @Override
    public List<User> findAllTeachers() {
        UserQuery query = new UserQuery();
        query.setRole(User.ROLE_TEACHER);
        query.setCurrentPage(1);
        query.setPageSize(Integer.MAX_VALUE);
        return findList(query, 0, Integer.MAX_VALUE);
    }

    private List<Object> appendQueryConditions(StringBuilder sql, UserQuery query) {
        List<Object> params = new ArrayList<>();
        if (query.getRole() != null) {
            sql.append(" AND u.role = ?");
            params.add(query.getRole());
        }
        if (query.getStatus() != null) {
            sql.append(" AND u.status = ?");
            params.add(query.getStatus());
        }
        if (query.getClazzId() != null) {
            sql.append(" AND u.clazz_id = ?");
            params.add(query.getClazzId());
        }
        if (query.getGender() != null && !query.getGender().isEmpty()) {
            sql.append(" AND u.gender = ?");
            params.add(query.getGender());
        }
        if (query.getAgeMin() != null) {
            sql.append(" AND u.age >= ?");
            params.add(query.getAgeMin());
        }
        if (query.getAgeMax() != null) {
            sql.append(" AND u.age <= ?");
            params.add(query.getAgeMax());
        }
        if (query.getKeyword() != null && !query.getKeyword().isEmpty()) {
            sql.append(" AND (u.username LIKE ? OR u.real_name LIKE ? OR u.student_no LIKE ? "
                    + "OR u.email LIKE ? OR u.phone LIKE ?)");
            String pattern = "%" + query.getKeyword() + "%";
            for (int i = 0; i < 5; i++) {
                params.add(pattern);
            }
        }
        return params;
    }

    private void fillInsertParams(PreparedStatement ps, User user) throws SQLException {
        ps.setString(1, user.getUsername());
        ps.setString(2, user.getPassword());
        ps.setString(3, user.getSalt());
        setStringOrNull(ps, 4, user.getStudentNo());
        ps.setString(5, user.getRealName());
        ps.setString(6, user.getGender());
        setIntOrNull(ps, 7, user.getAge());
        ps.setString(8, user.getEmail());
        ps.setString(9, user.getPhone());
        ps.setString(10, user.getAddress());
        setStringOrNull(ps, 11, user.getAvatar());
        setIntOrNull(ps, 12, user.getClazzId());
        ps.setInt(13, user.getRole() != null ? user.getRole() : User.ROLE_STUDENT);
        ps.setInt(14, user.getStatus() != null ? user.getStatus() : User.STATUS_ACTIVE);
    }

    private User mapRow(ResultSet rs) throws SQLException {
        User user = new User();
        user.setId(rs.getInt("id"));
        user.setUsername(rs.getString("username"));
        user.setPassword(rs.getString("password"));
        user.setSalt(rs.getString("salt"));
        user.setStudentNo(rs.getString("student_no"));
        user.setRealName(rs.getString("real_name"));
        user.setGender(rs.getString("gender"));
        int age = rs.getInt("age");
        user.setAge(rs.wasNull() ? null : age);
        user.setEmail(rs.getString("email"));
        user.setPhone(rs.getString("phone"));
        user.setAddress(rs.getString("address"));
        user.setAvatar(rs.getString("avatar"));
        int clazzId = rs.getInt("clazz_id");
        user.setClazzId(rs.wasNull() ? null : clazzId);
        user.setRole(rs.getInt("role"));
        user.setStatus(rs.getInt("status"));
        int failCount = rs.getInt("fail_count");
        user.setFailCount(rs.wasNull() ? 0 : failCount);
        Timestamp lockUntil = rs.getTimestamp("lock_until");
        if (lockUntil != null) {
            user.setLockUntil(new java.util.Date(lockUntil.getTime()));
        }
        Timestamp createTime = rs.getTimestamp("create_time");
        if (createTime != null) {
            user.setCreateTime(new java.util.Date(createTime.getTime()));
        }
        try {
            user.setClazzName(rs.getString("clazz_name"));
            user.setMajorName(rs.getString("major_name"));
            user.setDeptName(rs.getString("dept_name"));
        } catch (SQLException ignored) {
        }
        return user;
    }

    private void setIntOrNull(PreparedStatement ps, int index, Integer value) throws SQLException {
        if (value != null) {
            ps.setInt(index, value);
        } else {
            ps.setNull(index, Types.INTEGER);
        }
    }

    private void setStringOrNull(PreparedStatement ps, int index, String value) throws SQLException {
        if (value != null) {
            ps.setString(index, value);
        } else {
            ps.setNull(index, Types.VARCHAR);
        }
    }

    private void setParams(PreparedStatement ps, List<Object> params) throws SQLException {
        for (int i = 0; i < params.size(); i++) {
            Object param = params.get(i);
            if (param instanceof Integer) {
                ps.setInt(i + 1, (Integer) param);
            } else if (param instanceof String) {
                ps.setString(i + 1, (String) param);
            }
        }
    }

    @FunctionalInterface
    private interface ParamSetter {
        void set(PreparedStatement ps) throws SQLException;
    }

    private User queryOne(String sql, ParamSetter setter) {
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement(sql);
            setter.set(ps);
            rs = ps.executeQuery();
            if (rs.next()) {
                return mapRow(rs);
            }
        } catch (SQLException e) {
            throw new RuntimeException("用户查询失败", e);
        } finally {
            DBUtil.close(conn, ps, rs);
        }
        return null;
    }
}